1. Field of Invention
The present invention relates generally to the field of interconnect structures. More specifically, the present invention is related to a novel interconnect structure having voids whose size may vary according to electro-migration, and a method for use with the same.
2. Discussion of Related Art
Non Von-Neumann computational architectures show considerable promise for offering significantly faster ways to solve some classes of problems. Synaptic elements offer one of many ways to create a non Von-Neumann architecture. Any material that exhibits at least two resistance states can in principle offer a path to mimic a synaptic element between any two neurons. However, materials exhibiting only bi-stable states offer only limited architecture possibilities. Ideally a material that is capable of multiple or continuously varying stable resistance states will provide the greatest flexibility for design and be closer to allowing mimicking the brain's learning or adapting function. Many materials that have been researched as storage or memory elements can serve as a synaptic element but often require complex integration schemes.
Some examples include phase change memory (PCM) materials, resistive random access memory (RRAM) materials and spin torque transfer (STT) magnetic tunnel junctions, to name a few. All of them have some drawbacks, which can be managed with additional complexity. For example, in phase change materials, it is easy to decrease the resistance by incrementally crystallizing the glassy material, but is it is not possible to slowly increase the resistance (without melting, quenching and/or heating) to reach the desired higher resistance. This adds a lot of circuit complexity and iterations to hit the desired higher resistance state. RRAM materials typically only exhibit two stable states making for limited usefulness. STT junctions offer variable resistance but they tend to relax to their ground state which raises issues of stable states. Further, in STT junctions the electrical resistance contrast between the two stable states is very limited.